The women's 4 × 100 metre freestyle relay at the 2025 World Aquatics Championships was held on 27 July 2025 at the World Aquatics Championships Arena at the Singapore Sports Hub in Kallang, Singapore.

Background The event was expected to feature a close contest between Australia, the United States, and China. Australia, long dominant in the event, fielded a younger and less experienced team than in previous years, and Mollie O’Callaghan and Meg Harris were expected to lead the relay. Their cumulative individual 100-metre times from the 2025 Australian Trials were 3:33.61 which was their slowest since 2021, but with Harris absent from the trials final and O’Callaghan not at full effort, they were expected to be faster in Singapore. The United States, with Torri Huske, Gretchen Walsh, Kate Douglass, and Simone Manuel, appeared strong after a 3:31.20 cumulative trials time, their fastest since 2017. China, having lost Yang Junxuan, were relying on Wu Qingfeng and Cheng Yujie to pursue another podium finish.

Qualification Each National Federation could enter one team in the relay. The team had to be composed of swimmers who were also competing in the individual events, along with relay only swimmers who had to have met a specific qualifying time for the corresponding stroke and distance they would be swimming in the relay. Federations were only allowed to enter two relay-only swimmers for each relay they entered, though they could also enter relay-only swimmers from other relays which did not count toward this limitation.

Records Prior to the competition, the existing world and championship records were as follows.

Heats The heats took place on 27 July at 12:32.

Rank Heat Lane Nation Swimmers Time Notes 1 1 4 Erin Gemmell (53.52)Kate Douglass (52.04)Anna Moesch (53.80)Simone Manuel (54.21) 3:33.57 Q 2 2 4 Olivia Wunsch (53.70)Abbey Webb (53.98)Hannah Casey (53.86)Milla Jansen (53.10) 3:34.64 Q 3 1 6 Milou van Wijk (54.09)Femke Spiering (54.65)Sam van Nunen (54.36)Marrit Steenbergen (52.37) 3:35.47 Q 4 2 5 Cheng Yujie (53.60)Liu Yaxin (53.92)Yang Wenwen (54.20)Wu Qingfeng (53.91) 3:35.63 Q 5 2 3 Béryl Gastaldello (54.10)Marina Jehl (54.27)Albane Cachot (53.91)Marie Wattel (53.48) 3:35.76 Q 6 1 1    Neutral Athlete B Daria Trofimova (53.73)Aleksandra Kuznetsova (54.01)Daria Surushkina (54.43)Daria Klepikova (53.78) 3:35.95 Q, NR 7 1 3 Sara Curtis (53.59)Chiara Tarantino (54.59)Sofia Morini (54.36)Emma Virginia Menicucci (54.13) 3:36.67 Q 8 2 6 Nikolett Pádár (55.12)Panna Ugrai (54.86)Petra Senánszky (53.60)Lilla Minna Ábrahám (53.46) 3:37.04 Q 9 1 5 Brooklyn Douthwright (54.36)Taylor Ruck (53.37)Sienna Angove (54.79)Ingrid Wilm (54.98) 3:37.50 10 1 2 Nina Holt (54.36)Nina Jazy (54.54)Julianna Bocska (54.64)Lise Seidel (54.76) 3:38.30 11 2 2 Julie Kepp Jensen (54.82)Elisabeth Ebbesen (54.39)Schastine Tabor (55.73)Helena Rosendahl Bach (55.72) 3:40.66 12 2 7 Olivia Nel (54.91)Caitlin de Lange (56.00)Georgia Nel (56.38)Hannah Robertson (58.04) 3:45.33 13 2 1 Jo Hyun-ju (54.97)Hur Yeonk-yung (54.72)Lee Lee-na (57.77)Kim Do-yeon (58.18) 3:45.64 1 7 Did not start

Final The final took place at 20:18.

Rank Lane Nation Swimmers Time Notes 5 Mollie O'Callaghan (52.79)Meg Harris (51.87)Milla Jansen (52.89)Olivia Wunsch (53.05) 3:30.60 4 Simone Manuel (53.09)Kate Douglass (51.90)Erin Gemmell (53.17)Torri Huske (52.88) 3:31.04 3 Milou van Wijk (53.27)Tessa Giele (54.13)Sam van Nunen (54.85)Marrit Steenbergen (51.64) 3:33.89 4 6 Cheng Yujie (53.42)Liu Yaxin (53.93)Yu Yiting (53.88)Wu Qingfeng (52.94) 3:34.17 5 2 Béryl Gastaldello (53.58)Marina Jehl (54.12)Albane Cachot (53.95)Marie Wattel (52.97) 3:34.62 NR 6 7    Neutral Athlete B Daria Trofimova (53.77)Aleksandra Kuznetsova (54.00)Alina Gaifutdinova (54.24)Daria Klepikova (52.68) 3:34.69 NR 7 1 Sara Curtis (53.29)Emma Virginia Menicucci (53.87)Chiara Tarantino (53.75)Sofia Morini (54.27) 3:35.18 NR 8 8 Minna Ábrahám (53.97)Petra Senánszky (53.85)Panna Ugrai (54.41)Nikolett Pádár (54.11) 3:36.34 NR

Notes

References